A Las Vegas orthopedic surgeon has commissioned a $70 million explorer yacht not simply to indulge a passion for luxury, but to give his 12 grandchildren a chance to see some of the world’s most remote places. Dr. Steven C. Thomas, a lifelong sailor who crossed oceans long before he became a superyacht owner, has built the 152-foot Zembra around the kind of family adventures that first drew him to the sea.
Built by Seattle-based Delta Marine, Zembra combines the range of a transoceanic explorer with the polished comforts of a luxury family yacht. According to Delta Marine, the 152-foot full-displacement motor yacht is engineered for global travel, deep-sea dives, and aerial exploration, packing an extraordinary amount of expedition equipment into a vessel measuring under 50 meters and remaining below 500 gross tons.
A floating expedition base
Zembra’s most remarkable feature may be how much hardware is hidden inside its relatively compact hull. The yacht carries a two-seat ICON A5 amphibious aircraft, whose wings fold for storage before a bridge-deck crane lowers it into the water. From there, the aircraft can take off from the sea and reach a maximum speed of 95 knots, with a range of about 427 nautical miles with reserve. It can also land on conventional runways.
There is a helicopter landing area as well, although it appears to be intended for landing and touch-and-go operations rather than permanently carrying a helicopter. Thomas, his wife Karen and the yacht’s captain are reportedly helicopter pilots.
Below the waves, Zembra carries a three-person U-Boat Worx submersible capable of reaching around 1,000 feet. The approximately 8,400-pound craft accommodates one pilot and two passengers, has up to 12 hours of endurance and uses a 21.6-kWh lithium-ion battery. Its panoramic acrylic pressure hull, air-conditioned cabin, leather seats and automated depth and heading controls make it less like a cramped submarine and more like an underwater observation capsule. Thomas has already completed a certification dive to roughly 1,000 feet during testing in Norway.
The yacht’s lifting equipment is equally serious. A 3,500-pound bridge-deck boom crane handles the ICON A5, while a concealed stern gantry crane rated at approximately 10,000 pounds is used for the submarine. The latter is tucked into the bridge-deck overhang, leaving little visible when it is stowed. Guests can reportedly board the submarine from the yacht before it is lowered into the water. There is even another vessel hiding behind the scenes. A 50-foot aluminum catamaran is being built in British Columbia to serve as both a chase boat and submarine tender. With waterjet propulsion, it can make about 20 knots carrying the submarine and up to 40 knots without it, with roughly 400 nautical miles of independent range.
The adventure inventory continues with a 6.32-meter Williams DieselJet 625, two personal watercraft, a FunAir inflatable waterslide and extensive water toys. At Thomas’s request, the Williams has been converted into a wakesurf boat. A sundeck hot tub, large alfresco dining area and dedicated aft water-access spaces round out the outdoor setup.
Built around family, not just exploration
Despite all the expedition machinery, Zembra does not resemble a stripped-down commercial research vessel. Its metallic Arizona bronze exterior, large windows, clean angular lines and cut-down bulwarks give it a sleek, yacht-like appearance. The aircraft, tender and toys are stored inboard, allowing the profile to remain remarkably clean when everything is put away. Inside are five staterooms, including a full-beam master suite on the main deck and four large guest cabins below. One is wheelchair accessible, while an elevator connects all four decks. Wider circulation areas and a convertible cabin that can become a gym were incorporated with different generations and accessibility in mind.
The interior was created by Thomas’s brother, Roger Thomas, the celebrated designer behind numerous Wynn resort interiors. Reportedly coming out of retirement for the project, he brought a more theatrical sensibility to the yacht through custom cerused oak, stainless-steel accents and richly patterned carpets.
For Steven Thomas, however, the most important feature is not the submarine or aircraft. He and Karen have three daughters and 12 grandchildren, and the yacht is intended principally to show those grandchildren the world. The family plans to revisit destinations including the South Pacific, Brazil and the Mediterranean, with Costa Rica, Panama, Alaska and the Caribbean also among the potential cruising grounds.
That ambition is rooted in a lifetime at sea. Thomas and Karen once spent a year exploring the South Pacific aboard an 18-meter steel ketch, and later sailed around the world with their three young daughters aboard a 15-meter Prout catamaran. He subsequently owned an approximately 27-meter Inace explorer and a Nordhavn 86/90.
Even the name Zembra carries a personal story. As a teenager working aboard an oil tanker, Thomas saw the Tunisian island of Zembra shimmering in the Mediterranean and promised he would visit it. Years later, he deliberately turned away when approaching it, fearing that reality might spoil the dream. Now, rather than chasing one island, Thomas has built a yacht capable of chasing horizons with an entire new generation of his family.
